Tobacco smoke filter

ABSTRACT

A filter for removal of tar and other harmful substances from tobacco smoke which comprises two parts removably connected to each other and having complementary abutting frustoconical surfaces, one of which is provided with very shallow grooves through which the smoke passes at high speed, and at least one expansion chamber downstream of these grooves.

United States Patent [72] Inventor Giovanni Bottazzi 1,795,315 3/1931 Quest 131/210 Vla Ovada 15, Milan, Italy 2,385,651 9/1945 Rickets 131/ 187 [21] App]. No. 8,289 2,954,780 10/1960 Lebert 131/ 187 [22] Filed Feb.3, 1970 3,196,881 7/1965 Walters 131/210 X [45] Patented Jan.4, 1972 1,221,864 4/1917 Irving 131/216 X [32] Priority Feb. 3,1969 3,174,487 3/1965 Missler 131/210 X 1 y FOREIGN PATENTS [311 2363 M59 985,071 3/1965 Great Britain 131/210 531,296 10/1921 France 131/216 TOBACCO SMOKE FIILTER Primary Examiner-Joseph S. Reich 6 Claims 4 Drawing 5- AttorneyMichael S. Striker [52] US. Cl 131/210,

51 l t Cl ggy ABSTRACT: A filter for removal of tar and other harmful n A24fl3/04, substances from tobacco smoke which comprises two parts [so] Fi d f Search 131,210 removably connected to each other and having complementae o 20] 216, y abutting frusmconical Surfaces one of which is provided with very shallow grooves through which the smoke passes at [56] References Cited high speed, and at least one expansion chamber downstream uNrTED STATES PATENTS Pfthese 1,261,038 4/1918 Labreche 131/210 PATENTED JAN 4 B72 Fig. 2

Fig. 3

INVENTOR. I Q 'owwui 3071125: BY Muff @522:

TOBACCO SMOKE FILTER Filters for tobacco smoke are known which are used to remove tar and other harmful substances from the smoke. Such filters are generally made from metal and based upon a system which causes smoke to pass through a very thin hole, wherein the smoke will attain a high speed and then make it flow into a chamber or into a passage with larger diameter, or make it impact against a wall, in such a manner so as to obtain condensation of said tar and then the resulting deposit, by expansion, or by impact.

Said filters, however, show disadvantages which are up to now unresolved.

A first disadvantage being that the passage hole or thin holes for the smoke required a very delicate operation, resulting in a high cost of the filter.

Another disadvantage was that of the difficulty in cleaning said holes or thin channels. Obstrucfion of said channels or holes occurs very frequently, owing to the case at which tar hardens, and accordingly the cleaning was impaired and even a needle, or similar means were not suitable for cleaning, since a common needle has a diameter larger than the channel or channels.

This invention resolves said troubles, in that it permits to obtain said channel or channels for the passage of the smoke at a very low cost and in a very simple manner, still providing very thin channels. Moreover, the filter and the channels can be cleaned perfectly in an easy manner, for example using a toothbrush or finger nails.

The filter proposed by this invention comprises substantially two separate parts, one engaging into the other, said parts showing two annular juxtaposed surfaces and contacting each other, one of which being fitted with shallow grooves which together with the other surface will form very shallow channels for passage of smoke.

Preferably said two matching surfaces are of a cone-shaped configuration, and the outlet ends of the shallow channels communicate with an expansion chamber, in a manner that the tar and the other substances contained in the smoke will condense at the outlet of said channels.

According to a preferred embodiment of this invention, the filter is so shaped as to show a prefiltering portion, comprising a passage having a relatively large diameter communicating with a first expansion chamber and arranged upstream of said shallow passages, in a manner that the smoke can deposit a certain percentage of solid material along with the other suspended matter.

Moreover, said filter is equipped with projections suitable to prevent that tar will reach the suction end of the mouthpiece, both in the case of its application for smoking cigarettes or for smoking tobacco as in the case of pipes.

In such a manner a very high filter performance is obtained, so as to eliminate almost entirely the tar and other matter contained in the smoke.

One embodiment of this invention is represented by way of an example and not as a limitation in the attached drawing, wherein:

FIG. 1 is an axial cross-sectional view showing a first part of the filter acting also as a seat for inserting a cigarette;

FIG. 2 is a front view of said first part;

FIG. 3 is an axial section showing the second part of the filter;

FIG. 4 is an axial section showing the two parts of said filter coupled and mounted on a mouthpiece.

Referring now to said figures, the filter of this invention comprises a first part 1 (FIGS. 1, 2) and a second part 2 (FIG. 3). Said part 1 comprises a cylindrical shaped body showing at its front portion a cylindrical-shaped hollow seat 3 adapted to receive the end of a cigarette. The seat 3 is tapered at its rear end and joined to a threaded, bore 4 which in turn communicates with a bore 9 of larger diameter which terminates with a cone-shaped surface 5 onto which, at regular intervals, are one or more grooves or notches 6 of a very limited depth.

Said grooves or notches 6 can be executed very shallow, for example at a depth approximately a tenth of millimeter, in an easy operation, such as by compression or by means of a sharp tool.

The second part 2 of said filter shows at its front part a threaded end 7 adapted to enter and be screwed into the threaded bore 4 through part 1 (FIGS. 3, 4) and a contiguous cylindrically shaped portion 8 having a larger diameter and adapted to engage into the rear hole 9 of part 1, and forming, when the parts 1 and 2 are connected to each other, with the cylindrical-shaped wall of said hole an annular gap 10 of small radial dimension. Rearwardly of said cylindrical-shaped portion 8 at a cone shaped surface 11 is provided, the taper of which is equal to that of surface 5 of said portion 1, in a manner that said surfaces I1 and 5 can match perfectly, and in a manner that said grooves 6 will form very shallow passage channels.

The front end 7 of said portion 2 is provided with an axial hole 12 communicating with radial holes 13 reaching the cylindrical surface 8 and then the chamber 10, when said parts 1 and 2 are coupled together.

The part 1, shows at its rear part a recessed cylindrical portion 14 with a ledge 15 for frictional engagement with a mouthpiece 16 which is cylindricalshaped at least in the zone surrounding part 2 of the filter.

The body of said part 2 shows annular ribs 17, spaced one from the other, in a manner as to obtain annular chambers 18 for expansion of the smoke and into which condensate tar can deposit and flow, said annular ribs serving also to prevent said tar from flowing to the rear end of the filter, wherein some radial holes 19 connected to one axial hole 20 will permit the smoke to reach the rear end of the mouthpiece.

Obviously, after smoking one or more cigarettes, the user can easily clean the filter by removing said mouthpiece l6 and detaching said parts 1 and 2 from each other, in a manner to get a quick access to said channels 6 which in turn can also be cleaned from tar rapidly and easily by the use of a brush.

Of course, by making said channels 6 very shallow, it will be possible; to obtain a very high perfonnance in filtering the smoke. On the basis of tests carried out, it has been shown that the tar will deposit initially onto the outlet end of the channels and then gradually flow toward the collection chambers 18.

Said holes 12 and 13 and said chamber 10 are forming a tortuous path and a device for small acceleration and expansion of the smoke in a manner to promote a first deposit of tar. Hole 12 has a relatively large diameter, whereby it can easily be cleaned also by a jet of water, while said chamber 10 can easily be cleaned by separating said two portions.

Of course the filter can be executed in an other, difierent manner, provided the principle as per the present invention, is maintained without departing from the scope of the invention itself.

I claim:

1. A filter for tobacco smoke comprising a first forward part and a second part releasably connected to each other with a portion of said second part extending rearwardly beyond said first part, said parts having complementary frustoconical faces abutting against each other and one of said faces being provided with shallow grooves for the passage of smoke therethrough; pasage means in said first and second parts and communicating with said grooves; and a mouthpiece surrounding said portion of said second part and forming therewith at least one expansion chamber for the smoke passing through said shallow grooves, said parts having substanfially cylindrical releasable connecting means adjacent said faces and having a transverse diameter that is smaller than any transverse diameter of said faces.

2. A filter as defined in claim 1, wherein said grooves have a depth of about one-tenth of a millimeter.

3. A filter as defined in claim 1, wherein said first part is formed with an axial bore therethrough having a first portion, an intermediate portion provided with a screw thread and a rear portion of larger diameter than said intennediate portion,

' communicating at opposite ends with said first portion of said first part and said annular passage.

4. A filter as defined in claim 3, wherein said first bore portion in said first part forms a seat for the end portion of a cigarette, and wherein said bore means comprise means providing a first bore coaxial with said first bore portion in said first part and means providing a second bore transverse thereto and communicating with said annular passage.

- 5. A filter as defined in claim 1, wherein said mouthpiece has an inner cylindrical surface coaxially surrounding said rearwardly extending portion of said second part radially spaced therefrom and wherein the latter is provided with a plurality of annular ribs having outer edges closely adjacent to said inner cylindrical surface so as to form a plurality of successive expansion chambers for the smoke.

6. A filter as defined in claim 1, and including additional passage means formed in the rear end of said second part and including means providing a transverse bore communicating with the last of said plurality of expansion chambers, as viewed in the direction of the passage of smoke through the filter, and means providing a bore coaxial with said second part and communicating at opposite ends with said transverse bore of said additional passage means and the interior of said mouthpiece downstream of the rear end of said second part. 

1. A filter for tobacco smoke comprising a first forward part and a second part releasably connected to each other with a portion of said second part extending rearwardLy beyond said first part, said parts having complementary frusto-conical faces abutting against each other and one of said faces being provided with shallow grooves for the passage of smoke therethrough; passage means in said first and second parts and communicating with said grooves; and a mouthpiece surrounding said portion of said second part and forming therewith at least one expansion chamber for the smoke passing through said shallow grooves, said parts having substantially cylindrical releasable connecting means adjacent said faces and having a transverse diameter that is smaller than any transverse diameter of said faces.
 2. A filter as defined in claim 1, wherein said grooves have a depth of about one-tenth of a millimeter.
 3. A filter as defined in claim 1, wherein said first part is formed with an axial bore therethrough having a first portion, an intermediate portion provided with a screw thread and a rear portion of larger diameter than said intermediate portion, said second part having a front portion provided with a complementary screw thread threadingly engaged with said screw thread of said intermediate bore portion and rearwardly of said front portion a cylindrical portion closely adjacent to the inner surface of said rear bore portion of said first part so as to form therewith a shallow annular passage communicating with said shallow grooves and forming prefiltering means, said annular passage forming part of said passage means and the latter further comprising bore means in said second part and communicating at opposite ends with said first portion of said first part and said annular passage.
 4. A filter as defined in claim 3, wherein said first bore portion in said first part forms a seat for the end portion of a cigarette, and wherein said bore means comprise means providing a first bore coaxial with said first bore portion in said first part and means providing a second bore transverse thereto and communicating with said annular passage.
 5. A filter as defined in claim 1, wherein said mouthpiece has an inner cylindrical surface coaxially surrounding said rearwardly extending portion of said second part radially spaced therefrom and wherein the latter is provided with a plurality of annular ribs having outer edges closely adjacent to said inner cylindrical surface so as to form a plurality of successive expansion chambers for the smoke.
 6. A filter as defined in claim 1, and including additional passage means formed in the rear end of said second part and including means providing a transverse bore communicating with the last of said plurality of expansion chambers, as viewed in the direction of the passage of smoke through the filter, and means providing a bore coaxial with said second part and communicating at opposite ends with said transverse bore of said additional passage means and the interior of said mouthpiece downstream of the rear end of said second part. 